1. Field of the Invention
This invention relates to an image pickup device in which a so-called privacy mask is synthesized to an image, obtained on imaging, and the resulting synthesized image is transmitted to an external device.
This application claims priority of Japanese Patent Application No. 2003-338383, filed on Sep. 29, 2003, the entirety of which is incorporated by reference herein.
2. Description of Related Art
For imaging a news program, or preventing theft or the like acts, a monitor camera is frequently used. The monitor camera, installed on an image pickup site and kept there for a prolonged time, continuously images a subject for imaging, thereby enabling the status of the subject or the progress of the statuses to be observed in realtime. In addition, the image data, obtained on imaging, may be sequentially recorded on a preset recording medium for use for post-analyses.
If, in imaging a subject of interest by a monitor camera, if there is an article possibly infringing the privacy, such as a placard of a company or a window of the residence, referred to below as a private subject, in a near-by area, it is necessary to avoid imaging the subject of interest and the private subject simultaneously (see for example the Patent Publication 1). In EU nations, the imaging of such private subject is prohibited by law.
Thus, in imaging a subject with a monitor camera, mounted in position, there has so far been proposed a monitor camera device, having a privacy mask function, capable of locally screening an output image surface, obtained from image data of the monitor camera, with a view to avoiding the imaging of the private subject at the same time (see for example Patent Publication 1).
[Patent Publication 1] Japanese Laid-Open Patent Publication 2001-69494
In this conventional monitor camera device, having the privacy masking function, it is necessary to make the pickup image angle variable freely, as in a usual camera device, in order to enable zoom-up imaging for a specified object or monitoring of a broad range of the surrounding situation.
If, in such case, the broad-range imaging is to be executed by progressively enlarging the pickup image angle, the size of the privacy mask, displayed on the output image surface, needs to be decreased correspondingly. In similar manner, if the pickup image angle is progressively narrowed for zooming up a desired area, the privacy mask, displayed on the output image surface needs to be correspondingly increased in size. In case the privacy mask is displayed on the entire output image surface, especially in zoom-up, the image recording operation is unnecessary to perform on the side of the image recording device which records the image picked up by the monitor camera device.
However, the conventional monitor camera device suffers from a problem that, since the information pertinent to the size of the privacy mask, changed in dependence upon the pickup image angle, cannot be acquired on the side of the image recording device, the image recording operation which is unnecessary to perform on the side of the image recording device, is executed, especially during zoom-up.
On the other hand, it has so far been desired to achieve serial communication with the takeup ratio of the privacy mask in the output image surface as one parameter on the side of the image recording device.